Wrench



K. MULLER ENC Aug; 7, 1923.

Filed March 22, 1923 Patented Aug. 7, 1923.

KARL IZIU'LLER, OF KREIENSEN, GERMANY.

WRENCH.

Application filed March 22, 1923. Serial No. 626,982.

To 6125 whom it may 0071067370.

Be it known that 1, KARL Mi'iLLnR, a citizen of Germany, residing in Kreiensen, Germany, Harz, Am Brunstein 190, have invented new and useful Improvements in and lielating to Wrenches, of which the following is a specification.

My invention relates to improvements in screw wrenches, and more particularly in wrenches of the type in which one of the jaws is acted upon by a spring tending to force the same towards the other jaw and by a clamping member acted upon by the handle for forcing the same in clamping engagement with said other jaw. The object of the improvements is to provide a Wrench of this type which can readily be handled and which is reliable in operation. With this object in view my invention consists in constructing the wrench in such manner that the spring-pressed jaw is automatically locked in clamping position by the operation of the wrench, and remains locked when the handle is accidentally moved in a direction for opening the wrench.

In order that my invention be more clearly understood an example embodying the same has been shown in the accompanying drawing, in which the same reference characters have been used. in all the views to indicate corresponding parts. In said drawing,

Fig. 1, is a section of the wrench taken on the line 1-1 of Fig. 2, and

Fig. 2, is a section thereof taken on the line 22 of Fig. 1.

In the example shown in the drawing my improved wrench consists of a handle d having a jaw a mounted thereon by means of a pivot pin a, which jaw will hereafter be described as a relatively stationary jaw. The jaw a is formed with a guideway g which in the example shown in the figures is in the form of a cross. I do not limit myself, however, to this form. In the said guideway a relatively movable jaw c is mounted which is formed with an arm 7 fitting in the guideway and passing through a corresponding hole of the stationary jaw. The jaw c is formed with a socket or housing it enclosing a coiled spring 2', which spring bears with one end on the bottom of the socket and with its opposite end on a cross-piece 7' secured to the stationary jaw a. To the said cross-piece a pin 7: is secured. which provides a guide for the spring ary jaw 64 and cut out at its bottom along a circle exactly corresponding to a circular cam Z formed at the top end of the handle at and disposed eccentrically of the pin 0.

Preferably the engaging faces of the block m and the arm 7' are roughened to insure reliable contact between the parts and to lock the movable jaw against movement out of clamping position. Fig. 1 shows the Wrench with a blank a clamped between the jaws thereof.

The operation of the wrench is as follows: In the out of use position of the parts, the spring 2' forces the movable jaw 0 towards the stationary jaw. If it is desired to grip a blank a the diameter of which is larger than the relative distance of the jaws, the handle d is rocked in a counter-clockwise direction in Fig. 1, in order to unlock the block m and to release the arm of the movable jaw 6. Now the movable jaw is retracted by hand away from the stationary jaw and against the pressure of the spring 2', whereupon the wrench is applied to the blank n. N ow the movable jaw e is released and pressed by the spring 2' against the blank. Thereafter the handle (5 is rocked in a clockwise direction in Fig. 1 for forcing the block m by means of the eccentric cam Z into locking engagement with the arm f of the movable jaw 6. Now the jaw c bears on the blank with a pressure a multiple of the force exerted on the handle (Z, so that it can not be moved any more.

In screw wrenches of this type such as are now in use the movable jaw is not always securely locked in the position in which it clamps the blank, and the jaw is sometimes loosened and shifted by accident. By providing a wedge shaped locking member such as the block m acting on the inclined bottom face of the arm f unlocking of the jaw by accident is impossible, and locking of the closed jaws does not require any considerable force, because by reason of the beveled form of the block m the pressure on the arm f is sufficient to prevent sliding of the parts m and f relatively to each other, even if the contacting surfaces are comparatively smooth. For opening the wrench, the handle (Z is turned in a counter-clockwise direction in Fig. 1 and the block m is simultaneously shifted a little to the left, for loosening the parts m and f, whereupon the jaw e, which is now acted upon only by the spring 2', may be shifted to the left and away from the blank. Now the wrench can be removed from the blank.

. I claim:

1. In a wrench, the combination, with a handle having a cam face at one end of a pivotally mounted aw, a aw shiftable relativelyto said pivotally mounted j aw, and a block intermediate said shiftable jaw and .cam face adapted to be forced by said cam "face against said shiftable jaw, the engaging surfaces of the shiritable jaw and the block being inclined relatively to the direction of the movement of the shiftable aw, said :handle forming the only handle of the wrench.

2. A wrench including a relatively stationary jaw provided with a guideway, a relatively shittable jaw having an arm movably mounted in said guideway, a spring for moving the shiftable jaw in one direction, a locking block for said arm, said arm and locking block being provided with contacting surfaces arranged at an incline to the direction of movement of the shiftable movement of ie shiftable arm, and a handle pivotally connected to the relatively stationary aw and provided with a cam engaging said block for moving the latter.

In testimonythereof l: hereinto ai'iix my signature in the presence of two witnesses.

KARL MiiLLEn.

Witnesses EMIL Kornnmrrscn, ADOLF OELINGER. 

